The present invention relates to a passenger protection device of a vehicle, in which an inflator generates inflatable gas in a vehicle collision, particularly in a vehicle side collision, and thereby a curtain airbag is inflated downwardly along a side portion of a vehicle compartment to protect a head portion of a passenger.
Vehicles have been recently equipped with a curtain airbag to protect a passenger against an impact load acting from a vehicle side, in addition to an airbag to protect the passenger against an impact load acting from a vehicle front. That is, the curtain airbag is arranged in its folded state, for example, in a bellows-shaped folded state, on the inside of the vehicle compartment along a vehicle-body side portion (see a roof side and a front pillar), an interior material is provided at the vehicle-body side portion to cover the curtain airbag in the folded state, and an inflator to generate inflatable gas in a vehicle collision is connected to the curtain airbag such that the inflatable gas is supplied to the curtain airbag so as to inflate the curtain airbag downwardly along the vehicle-body side portion in the vehicle collision over an area including both a front seat and a rear seat.
A conventional curtain airbag, in general, comprises plural cells (small chambers), which are configured such that upper portions thereof are open in an inflated state of the curtain airbag, whereas lower portion thereof are closed in the inflated state of the curtain airbag, so that the inflatable gas from the inflator is supplied into the respective cells through a gas flowing passage formed at a connection portion which is provided at the upper portions of the cells.
When the above-described conventional curtain airbag is inflated, the above-described interior material is deformed (pushed out) by its inflation pressure, then the curtain airbag comes out of a gap formed between the vehicle-body side portion and a vehicle-outside end portion of the interior material. In this case, since the gas flows into the cells from their open upper portions, a base portion of the curtain airbag in the folded state expands so quickly that a smooth inflation of the curtain airbag as a whole may be prevented. Consequently, the base portion of the curtain airbag quickly expanding may apply a momentary load to the interior material, so that there is a concern that the interior material may be broken and scattered.
Japanese Patent Laid-Open Publication Nos. 2002-362293 and 2009-12688 disclose the passenger protection device of a vehicle to protect the passenger against the load of the vehicle side collision, in which the curtain airbag comprises the plural cells and a gas passage extending in a vehicle longitudinal direction is formed on an upper side of the cells in an inflated state of the curtain airbag. Herein, the prior art disclosed in the above-described patent documents has a structure in which the inflatable gas flows into the cells from the upper side when the curtain airbag is inflated, so this structure of the prior art may have the same problem as well.